You need a 5 x 5 box. Across the top you label fuels A, B, C, D, and E.
Along the side, you label launchers I, II, III, IV, and V.
Diagonally, you label, weeks, 1,2,3,4 and 5.
Find an example, and plug in the numbers. You don't need to think. All you need is a calculator.